Predicting regional scale benthic community structure in a soft sediment intertidal habitat
Start date: 21 May 2012
Species distribution modelling in marine ecosystems remains a challenge due to lack of data on the factors that structure marine biodiversity. The extent to which marine communities are structured according to physical or biological processes remains highly contentious. We investigated benthic community structure within the intertidal mudflats of Poole Harbour, collecting 5 cores from 80 sites on a 500 x 500 m grid in November 2009 to study the biota and an additional core for sediment analysis. Further cores were taken from 15 additional sites within the harbour on a 100 x 100 m grid in August and November 2010 and February and April 2011 to examine intra-year biomass variation. Flow velocity, depth, salinity, and patterns of wave exposure were determined using a 2-D depth-integrated hydrodynamic model of Poole Harbour, developed by HR Wallingford. Analysis using the Bio-Env routine in PRIMER v6, indicated that the combination of wave energy, % sand, algal cover and organic content of the substrate accounted for 34.5% of the variation in community structure. These results suggest that on the regional scale, while some variation in community structure (roughly one third in the case of Poole Harbour) can be explained by components of the physical environment and algal cover, biological interactions such as competition and predation are likely to also be important on this scale. Therefore, models aiming to predict the effects of environmental change on regional scale biodiversity patterns in this habitat should take into account the effects on biological interactions to improve their predictive ability. Further research into the effects of environmental change on biological interactions is warranted.